Aggregation vs Surface Segregation: Antagonism over the Magnetic Behavior of NiCr Nanoparticles.

Annealing is a valuable method for fine-tuning the ultrasmall magnetic properties of alloy nanoparticles (NPs) by controlling their sizes, modifying their surfaces, and affecting their magnetic interactions. Herein, we study the effect of moderate annealing (450 °C) on strongly interacting NiCr nanoparticle assemblies (0 ≤ atom % Cr ≤ 15) immediately after deposition. Concurrent temperature-dependent electron microscopy and magnetization data demonstrate the interplay of two competing factors, namely, enhanced particle aggregation and element-specific surface segregation, on the magnetic properties, with the former boosting and the latter suppressing them.

Defect-assisted electronic metal-support interactions: tuning the interplay between Ru nanoparticles and CuO supports for pH-neutral oxygen evolution.

Electronic metal-support interactions (EMSIs) comprise an area of intense study, the manipulation of which is of paramount importance in the improvement of heterogeneous metal nanoparticle (NP) supported catalysts. EMSI is the transfer of charge from the support to NP, enabling more effective adsorption and interaction of reactants during catalysis. Ru NPs on CuO supports show different levels of EMSI (via charge transfer) depending on their crystal structure, with multiple twinned NPs showing greater potential for EMSI.

Non-enzymatic and highly sensitive lactose detection utilizing graphene field-effect transistors.

Field-effect transistor (FET) biosensors based on low-dimensional materials are capable of highly sensitive and specific label-free detection of various analytes. In this work, a FET biosensor based on graphene decorated with gold nanoparticles (Au NPs) was fabricated for lactose detection in a liquid-gate measurement configuration. This graphene device is functionalized with a carbohydrate recognition domain (CRD) of the human galectin-3 (hGal-3) protein to detect the presence of lactose from the donor effect of lectin - glycan affinity binding on the graphene.

Gas-Phase Synthesis for Label-Free Biosensors: Zinc-Oxide Nanowires Functionalized with Gold Nanoparticles.

Metal oxide semiconductor nanowires have important applications in label-free biosensing due to their ease of fabrication and ultralow detection limits. Typically, chemical functionalization of the oxide surface is necessary for specific biological analyte detection. We instead demonstrate the use of gas-phase synthesis of gold nanoparticles (Au NPs) to decorate zinc oxide nanowire (ZnO NW) devices for biosensing applications.

Observation of Metal to Metal Oxide Progression: A Study of Charge Transfer Phenomenon at Ru-CuO Interfaces.

Surface charge and charge transfer between nanoclusters and oxide supports are of paramount importance to catalysis, surface plasmonics, and optical energy harvesting areas. At present, high-energy X-rays and theoretical investigation are always required to determine the chemical state changes in the nanoclusters and the oxide supports, as well as the underlying transfer charge between them. This work presents the idea of using chrono-conductometric measurements to determine the chemical states of the Ru nanoclusters on CuO supports.